1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device connecting between an inverter and a lamp without a solder.
2. Discussion of the Related Art
Recently, flat panel display devices such as liquid crystal display devices, plasma display panels and organic light emitting diode based displays have been developed as substitutes for CRT (cathode ray tube) based displays.
In particular, the liquid crystal display (LCD) device are widely used as the displays of cell phones, portable computers, desktop monitors and liquid crystal televisions because of the high contrast ratio, low power consumption and suitability for displaying moving images that are characteristics of LCD devices.
Generally, a liquid crystal display device includes a liquid crystal display panel and a backlight unit. The liquid crystal display panel includes a thin film transistor substrate, a color filter substrate and a liquid crystal layer sandwiched between the thin film transistor substrate and the color filter substrate. The backlight unit is disposed at the rear of the liquid crystal display panel to provide light to the rear surface of the thin film transistor substrate. A backlight unit is provided because the liquid crystal display panel is not a self-illuminating device.
Backlight units may be broadly classified as edge type and direct type units according to the position of the light source relative to the liquid crystal display panel. The edge type backlight unit is most often employed in smaller sized the liquid crystal display such as those used in cell phones, notebook personal computers, and desktop monitors, while the direct type backlight unit is more typically employed in larger sized liquid crystal display devices such as liquid crystal televisions.
FIG. 1 illustrates a liquid crystal display with a typical edge type backlight unit. The liquid crystal display device 1 includes a liquid crystal display panel 10, a light guide plate 20 disposed at the rear of the liquid crystal display panel 10, and a light source 30 disposed at one side of the light guide plate 20. The liquid crystal display panel 10 includes a thin film transistor substrate 11 and a color filter substrate 12. Light emitted by the light source 30 enters at the one side of the light guide plate 20 and exits the light guide plate 20 at a surface at the rear of the liquid crystal display panel 10. A diffusion sheet, a prism sheet and a protection sheet 15, 16, and 17 are provided between the liquid crystal display panel 10 and the light guide plate 20. A reflective sheet 40 is disposed between the light guide plate 20 and a lower cover 50. A light source reflector 37 partially surrounds the light source 30. Light emitted by the light source 30 is reflected by the light source reflector 37 to enter a side surface of the light guide plate 20.
A CCFL (cold cathode fluorescent lamp), a HCFL (hot cathode fluorescent lamp) and an EEFL (external electrode fluorescent lamp) may each be employed as the light source 30 of the liquid crystal display device 1. As shown in FIG. 2, a CCFL, HCFL or EEFL for use as the light source 30 typically includes a cylindrically shaped glass tube 31, lamp electrodes 32 provided on each of the ends of the glass tube 31, and a lamp wire 33 connected between an inverter 34 and the lamp electrodes 32. An inverter 34 is connected to the lamp electrodes 32 through connector 35, and the lamp wire 33 is connected to the lamp electrodes 32 using solder.
However, the soldering process for connecting the lamp wire 33 to the lamp electrodes 32 uses a series of steps such as disposing the lamp wire 33 adjacent to the lamp electrodes 32, applying solder to the lamp wire 33 and the lamp electrode 32, and applying heat to the solder for connection between the lamp wire 33 and the lamp electrode 32. Accordingly, the soldering process uses a long time, thereby increasing production time and reducing the efficiency of the assembly process. Moreover, a malfunction causing contaminant may be introduced during the soldering process. Finally, an impact may separate the solder from the lamp wire 33 and the lamp electrode 32.